OBJECTIVE Air-polishing is routinely used for professional tooth cleaning. Therefore, the aim of this in vitro study was to evaluate the influence of different air-polishing powders on dentin bonding. METHODS Dentin bond strengths of a resin composite (Clearfil AP-X) bonded with different classes of adhesives (4-step etch-and-rinse: Syntac; 3-step etch-and-rinse: OptiBond FL; 2-step etch-and-rinse: Single Bond Plus; 2-step self-etching: AdheSE, Clearfil SE Bond, Clearfil Protect Bond, One Coat Self-Etch Bond; all-in-one/mix: Xeno III; all-in-one/no mix: Clearfil S3 Bond, G-Bond) were measured on flattened dentin surfaces. In test groups, specimens were air polished with Prophypearls (calcium carbonate) or ClinPro Prophypowder (glycine) prior to bonding. Microtensile bond strengths were evaluated after 24 h of storage at 37 degrees C in water. Surfaces and resin-dentin interfaces were observed by SEM, TEM, and CLSM. RESULTS Mean bond strengths varied from 18 to 73 MPa in control groups. Calcium carbonate air polishing generally caused significantly reduced dentin bond strengths (p < 0.05). TEM exhibited severe nanoleakage after calcium carbonate air polishing. Glycine did not affect dentin bonding performance of the adhesives under investigation. CONCLUSIONS Calcium carbonate air polishing should be avoided when dentin-bonded restorations are applied. Glycine powder is an alternative.